Railway block system and power supply circuit



Sept. 19, 193.9. -J. c. MCDONALD RAILWAY BLOCK SYSTEM AND POWER SUPPLY CIRCUIT Filed Feb.- 11, 1938 2 Sheets-Sheet 1 as wx P INVENTOR. J01w (3* QTOJDMMIZO I ATTORNEY I .25 wan/ gt; 2

Sept. 19, 1939. J, c c o 2,173,123

RAILWAY BLOCK SYSTEM AND POWER SUPPLY CIRCUIT Filed Feb. 11, 1938 2 Sheets-Sheet 2 1 car- E 102 90" 55 7 1 56 i 4 00 f mag 94 g/ 62 1: a 96 l 40? E BY ATTORNEY.

Patented Sept. 1 9, 1 939 Z, 1 l

UNITED STATES PATENT OFFICE RAILWAY BLOCK SYSTEM AND POWER SUPPLY CIRCUIT John C. McDonald, Beechhurst, Long Island, N. Y. Application February 11, 1938, Serial No. 190,121

10 Claims. (Cl. 246-34) My invention relates broadly to railway train after more fully set forth, with reference to the control and signalling systems and more paraccompanying drawings, in which: ticularly to an automatic voltage regulating cir- Figure 1 is a schematic diagram of the track cuit in a railway block system. and wayside control circuits; Fig. 2 is a schematic 5 One of the objects of my invention is to prodiagram of the cab signal and control circuits em- 5 Vide a simplified railway block signal system bodying my invention; and Fig. 3 is a modified employing a minimum of component parts, and form of track circuit for speed control in isowhich is relatively inexpensive and simple to lated blocks.

maintain, with dependability and safety more This invention is an improvement in the autofully achieved than has heretofore been obmatic train control and signalling systems dis- 10 tained. closed in my copending application Serial Num- Another object of my invention is to provide her 117,929, filed December 28, 1936, now Patent a track signal control circuit having automatic 2,110,960, the improvements relating particularly voltage regulation so that extended track secto the voltage regulation circuits and the signal tions may be employed without altering the and control elements directly in connection there- 15 voltage of the supply, and operation at low voltage with. In order that my invention may be more in the track circuit may be effected. clearly understood, I have illustrated the major Still another object of my invention is to prosignal and control circuits substantially as shown vide signal means in combination with the autoin my copending application, but with the supply matic voltage regulating circuit at the exit of a circuits and related signal and control circuits 20 block, for signalling workers in the vicinity of modified in accordance with my present invena train in the block ahead. tion.

A further object of my invention is to provide Track circuits now generally in use broadly cona block signal system for railroads and special sist of a source of current connected with the rails voltage supply circuits for the track in the several at relatively high voltage through a current lim- 25 blocks adaptable to blocks of indefinite length for iting impedance. The presence of a train in a seccoordination with modern high speed train opt1on shorticircturdts thle rgils and currdent from 3118 eration. source is imi e on y y the impe ance in e A still further object of my invention is to circuit. Such systems commonly require 12 to 18 provide low power apparatus for standard use watts power for each section, and where alter- 30 regardless of the length of track section to be fed, nating current is employed with an impedance of the voltage applied to the rails being of low value low power factor, a one kilowatt transformer 1n and automatically controlled in accordance with each track CIIITCUHJ is found tnecessary because of track conditions in the section or block. the hea ing e ect of the wa t-less current. Fur- Still another object of my invention is to prothermore, such track circuits are limited to sec- 35 vide a control circuit which avoids the use of O S O e to tWO t d yards, dependent current limiting reactors, such as are ordinarily upo e ballast impedance of the a b d at employed to prevent excessive currents in the rails the a v y gh llne Voltages u 00 of when a section is occupied, and which result in thlS length are lllladeqllate for the p t hlgh low power factor conditions in the supply under Speed trams, Whlch at Speed Of One hundred 40 load. I provide instead a voltage regulating ggcg g g g gg g i gg fg ggfi g r zz;- circuit by which the current in the tracks is reduced to substantially zero under short circuit gg gi g gi f gg 33 3352 35? 3; 33; condltfins 2 h f 5.1 1 221 2? and maintenance must be assured. The system appara us 0 P cu re 1 l p of my invention effectively provides for all of this, Another ObJeCt 0f "W is O prom e and may be employed with section lengths sev- Voltage rf3gu1atmg clrcult m the supply'sys' eral times as long as present sections, where tems of tram control relays f the cab slgeal feasible, as in parts of the western United States.

circuits as well as in the track signal control an The System f track Supply f my invention 50 cu whi insures uniformity in the system n is based on a voltage regulation circuit involving simplicity in operation and maintenance, as will phase hift in oppositely related current combe understood from the following specification. ponents, the phase shift being provided by im- Other and further objects of my invention pedance in the track circuit. Such impedance r reside in the circuits and arrangements hereinis conveniently provided in the inductive react- 2 ance and the resistance of the winding of the track relay connected at the entrance of a section, and the resistance of the rails and the ballast resistance in the track bed across the ties up to the exit of the section where the source is connected. As the impedance is thus usually inductive, the circuit may be considered as providing a leading voltage at the entrance of the section to draw the current from the source in complement to the pressure character of the voltage at the source. In furtherance of this View, it should be noted that increase in the length of the track section and the increase in resistance thus encountered, result in an increase in the phase shift and greater voltage on the rails so that substantially the same current conditions are maintained independently of the length of the block. When the section is occupied, the factors producing the phase shift are effectively shunted so that the voltage in the rails is reduced substantially to zero, and the current likewise, regardless of the length of the track section. With the low voltage applied to the rails, the ballast resistance through the road bed is high and the current is confined to the rails.

Referring to the drawings in detail, Fig. 1 shows the arrangement of track related apparatus in schematic form. It will be understood that the track sections may be of various lengths and that the connections to the track are made substantially at the entrance and exit ends, as indicated, while the signal and control apparatus is arranged at any convenient or desired location in the track section. The control system is the single line arrangement of my copending application Serial Number l17,929, now Patent 2,110,960, and no other interconnection or intercoupling is employed between sections.

In Fig. 1 I have shown blocks A, B, C and D, the circuits with respect to block B being shown in detail, with connections to the track relay in the forward block C. The direction of the train is from block A towards block D. Corresponding parts in block C are designated by like primed reference characters. In block C, rails 5', 6, are connected with power lines I through transformers 2, 3, arranged in a manner to be fully described hereinafter. Also connected with the rails 5', 6', is the winding of relay 1' which is disposed adjacent the entrance of the block C. Relay 1 is normally energized through the rails and is deenergized by the shunt created by presence of a train in the block 0. Contacts of relay 1 actuate signal and control means in block B in accordance with track conditions in block C, and also control the operation of speed control means in the block C, through relay l6, similarly as relay 1 in block B controls relay l6 when the relay i5 is conditioned by contacts on relay 1' in accordance with track conditions in block C.

In block B, relay 1 is energized through rails 5 and 6, similarly to relay '1 in block C. This track circuit is a principal feature of my invention and includes two transformers connected in a balanced parallel relation with provision for deriving voltage therefrom for the rails and current for signalling purposes. A transformer 2 has the primary 2a thereof directly connected across the power lines I; and a similar transformer 3 has the primary 3a thereof connected across the power lines I through the rails 5, 6, and the winding of relay 1. The secondaries 2b and 3b are connected with the voltages thereacross in phase opposition for conditions of short-circuit across rails 5, 6; this condition is indicatedat 60 as due to occupation of block B, and the secondary voltages are equal so that no current flows in the secondary loop 2b, 31). With the block B unoccupied by a train, the rails 5, 6, are not shunted and the track circuit is completed through the winding of relay 1. Inductive impedance found in the rails and the relay winding causes phase shift in the current flowing in the primary 3a of transformer 3, and consequently a shift in the phase of the voltage across the secondary 3b and a current results in the secondary loop 2b, 3b. The windings in the secondary loop are connected in reverse order and in phase opposition, as indicated in the drawings. This current is made available to operate a signal indicator at 4 at the exit end of the block B to indicate clear track to gangs of workmen possibly employed at this location, or in block C, or to a train advancing through block C towards block B which might otherwise meet a train coming from block A in head-on collision. This latter danger is effectively eliminated by the arrangement of my invention as occupied track conditions in the backward block B are indicated forward to block C by the current conditions in the secondary loop 2b, 311, through indicator 4.

Another indication is afforded by virtue of the current variations in the secondary loop 21), 3'0. Open circuit condition, such as may be caused by a broken rail, results in the removal of voltage at the primary 3a and consequent removal of the bucking voltage in the secondary 3b. The current in the secondary loop 21), 3b, accordingly increases, through indicator 4, and warns of the faulty track condition which prevents normal operation of the system.

The following data is representative of the track circuit conditions, track unoccupied, under the operation above detailed:

Line voltage 120 volts Relay and track impedance 2 ohms Phase shift in primary 3a 1 10 With the track occupied, the phase shift is reduced substantially to zero, and the track voltage and current and the secondary loop current likewise. The broken rail, open circuit condition would be somewhat different: track current would be zero and the secondary loop current approximately 10 amperes; while the track voltage would be approximately zero due to the induced voltage in the pricary 3a from the secondary 3b, which substantially cancels the line voltage.

The same arrangement may be employed for energizing the speed control elements, as shown in Fig. 1 at transformers 8 and 9, the primary 9a being connected, like the primary 3a, in series with a reactive load in across. the lines I. The load If! is adapted to be shunted by contacts [4 controlled by relay It for deenergizing lamps l! and I2, which are energized by the potential drop across the load l0.

Relay I5 is adapted to effect a quick break but slow make in the circuits controlled by the contacts of the relay which is energized from the lines I through contacts of both relay 1 and relay 1. There is a direct circuit through one contact I3 and arm H on relay I to energize relay l6 when block C is unoccupied; but When block C is occupied, contacts IT, IS, are opened and the relay I6 is controlled by contacts I9, 20, and 20a of relay 1 when a train enters block B. When relay I drops, upon occupation of block B by a train, contact arm I9 momentarily opens the circuit to relay I8 causing it to drop and energize lamps II, I2. The circuit to relay I6 is immediately restored through contact 28a and relay I6 may remake the shunt across load I8 after a predetermined time for transfer of the signal to the train for automatic control of the speed thereof, as will be explained.

Wayside signal lamps are shown as green at 50, yellow at 62, and red at 10, of the conventional significance. The green lamp 58 is lighted continuously when block C is unoccupied, through contacts 52', 53', which energize a series circuit including load reactors and 54, lamp 50 being energized by the potential drop across reactor 54. Simultaneously the potential drop across reactor 5| is applied to lamp 58 for actuating a cab signal. The yellow lamp 62 is connected similarly across a reactor 63 in series with reactor 6| and contacts 52', 53a, in relay I, with control lamp 64 connected across reactor 6|. The red lamp I8 is likewise connected across a reactor II in series with reactor 69 and contacts 61, 68a, in relay I, with control lamp 12 connected across reactor 69. Lamps 62 and I8 are thus both lighted with block C occupied and relay I dropped, and may be disposed at spaced intervals along block B for proper coordination in the system.

The positions of control lamps I I, I 2, 58, 64, 12, along the wayside, are determined relatively in diiTe-rent planes with respect to the side of the train so that individually responsive photo-sensitive devices may be provided on the train, as indicated in Fig. 2. The cab circuits shown in Fig. 2 are substantially the same as described in my copending application I I1, 929, with the substitution of the power supply circuit hereinbefore described for the supply circuit shown in that application. An alternating current power supply is indicated at 25, feeding lines 26. Transformers 2! and 28 are connected, like transformers 8 and 9, Fig. l, to provide a potential difference across an inductive load comprising the windings of relays 38, 34. Relay 38 is of the slow break, quick make type, and includes sets of contacts (H and 32. Relay 34 is conventional and includes contacts 35. Means for short-circuiting the inductive load of relays 38, 34, is provided in contacts 38 controlled by the winding of a relay 38, which also controls sets of contacts 39 and 48.

Relay 38 is energized from source 25 through switch contacts M of a relay I22, operated from a source II8 through photosensitive device II1 under control of lamps H, I 2, at the wayside. In normal position, as shown, contacts 36, 39 and 40 are open, and the windings on relays 38, 34. are energized. Brake control valves 45 and 46 are provided with release devices normally held closed by current from source 25. The actuating winding in valve 45 is connected through contacts 35 and 3!; and the actuating winding in valve 46 is connected through contacts 32. Contacts 35 open immediately upon the operation of the photosensitive device II! which results in the application of service brakes by means of valve 45 to check the speed of the train.

Operation of relay 38 places a shunt across contacts 4| of relay I22 through contacts 39 and a normally closed manual switch 41, thereby holding relay 38 energized. If this shunt is maintained sufficiently long, relay 38 operates to open contacts 32, which results in the application of emergency brakes by means of valve 46. The effeet of the opening of contacts 32 may be prevented by manual operation of switch 48 in shunt thereof; and the release of both service and emergency brakes may be effected by operation of switch 41, reenergizing relays 38 and 34. It should be noted, however, that application of the service brakes under control of lamps II, I2, on the wayside cannot be prevented.

The cab circuits for actuating the signal lamps derive power from the source 25 through transformer circuits similar to that of transformers 2, 3, and 8, 9, in Fig. 1. Transformers I3 and I4 are connected to provide a voltage across an inductive load comprising the winding of relay I8; and transformers I5 and I6 are connected to provide a voltage across the inductive load including the Winding of relay I9. Relays I8 and I9 control the operation of a plurality of circuits through contact arms 85, 89, and 81, 9|, respectively.

Relay contacts 88 of relay I2I, operated from source II8 through photosensitive device IIG under control of lamp I2 at the wayside, are connected in shunt with the winding of relay I9 and when closed cause contact arm 81 to drop, opening a circuit from the source through green signal lamp 84 and contact 88, and closing a circuit through contact 88a and yellow signal lamp 92 to the source. At the same time, contact arm 9I is dropped and a circuit completed through the winding of relay 98, contacts 94 of relay 83, and contacts 95 of relay I82. Operation of relay 96 closes contacts 91 which shunt the contacts 88 through contacts I88 of relay I82, and thus maintains relay I9 deenergized.

Relay contacts 8I of relay I28, operated from source II8 through photosensitive device II5 under control of lamp 64 at the wayside, are connected in shunt with the winding of relay I9 and when closed cause contact arm 85 to drop, opening the circuit through contact 86 to contact arm 81 of relay 19 and deenergizing yellow lamp 92, and closing a circuit through contact 86a directly to the red lamp I8I for energizing the red signal lamp. At the same time, contact arm 89 is dropped and a circuit completed through the winding of relay I92, contacts of relay 38, and contacts 93 of relay 83. Operation of relay I 82 opens contacts I88, removing the shunt on relay I9, and also opens contacts 95 to deenergize directly the relay 96. Contacts I83 are closed to complete a shunt circuit through contacts 98 of relay 96 on contacts BI and thus maintain relay I8 deenergized. Reenergization of relay I9 does not affect the signal circuits as the red lamp I9I only is connected through contact arm 85 of relay I8.

It will be noted that operation of relay I82 depends upon the condition of relay 38 and relay I82 will not be energized if the brake control circuit has already been actuated. The signal circuits thus retain the caution indication of yellow lamp 92, subject to restoration to normal or green lamp signal 84 by operation of contacts 82. Relay H9 is operated from the source II8 through photosensitive device H4 under control of lamp 58, and relay contacts 82 when closed complete the circuit to the winding of relay 83 which operates to open the circuits to relays 9G and I82, deenergizing whichever one, if any, is operative. Relays I8 and I9 thus are restored to operative condition and the green lamp 84 again lights. Operation of the brake control system by contacts M and relay 38 may restore the green signal circuit, but as the brakes are automatically applied the signal is disregarded; moreover, if the brakes are released and the train proceeds, other indications may promptly alter the green signal and the brakes may be again applied.

The speed control system may be applied to isolated blocks, independent of the signal system, for controlling the speed of trains on sections of bad road bed, at bridges, curves or grades, in the manner shown in Fig. 3. Double primed reference characters indicate the required elements which are connected and operative in the same respect as described with reference to Fig. 1.

Referring to the system as a whole, Figs. 1 and 2, and considering clear tramc in block C, a train entering block B, as at 60, will find conditions as indicated in Fig. 1; that is, green signal lamp 5% will show lighted at the wayside and control lamp, or lamps, 58 will be lighted at a selected position or positions along the block so that the clear track signal 84 may be maintained in the cab. All other circuits in block B are inoperative as the condition of relay 1 in block C precludes operation thereof.

Considering now that the train has passed into block C, creating a condition for block B of an occupied block ahead. A train entering block B as at 59 will find yellow and red signal lamps lighted at selected positions along the block, and control lamps 64 and I2 operative to actuate the yellow and red signal lamps in the cab as the train passes the control positions. Moreover, control lamps I l and I2 are energized by the train upon entering the block so that the brake control system in the cab may be operated if the danger conditions ahead remain. Ihe emergency application of brakes would follow unless prevented by the driver, as hereinbefore shown.

Clearance of the section ahead, block C, results in restoration of the green signal at the wayside and operation of control lamp 58 which will convey the signal to the cab as the train passes the control position at reduced speed. If the train has been forced to stop, the wayside signal 50 indicates clear track and the train may proceed. The restoring action of control lamp 58 through relay H9 and contacts 82 is available within block B when block C is cleared before the automatic brake control system is actu ated by control lamp l I, I2, and results in showing the green signal 84 in the cab, whereupon full speed may be resumed and the effect of the automatic control prevented by holding the switch 4'! open.

I have indicated in the drawings the loop circuits including the secondary windings of each of the transformer circuits in opposed phase, one with respect to the other. It will be understood that instead of connecting the secondary windings in phase opposition, I may connect the primary windings in reverse order or phase opposition. Either method of connection may be employed.

It will be understood that duplicates of all control lamps may be arranged along the block and the relative positions thereof selected in ac cordance with road conditions for maximum efficiency of operation.

While I have described my invention in certain preferred embodiments, I do not intend that my invention shall be limited thereby and I desire that it be understood that modifications may be made within the scope of the appended claims.

What I claim as new and desire to secure by Letters Patent of the United States is as follows:

1. In a railway block system including a control device having reactive characteristics, a source of alternating current, a transformer having primary and secondary windings, a circuit comprising said source and said primary winding connected in series with said control device, said device being constituted to alter the phase relation of the voltage of said secondary winding, a second transformer having a primary winding directly connected to said source and a secondary winding, connections between terminals of like polarity on said secondary windings, and means fOr shunting said control device, the voltages of said secondary windings being in phase opposition with said control device shunted by said means.

2. In a railway block system including a control device having reactive characteristics, a source of alternating current, a pair of transformers having primary windings connected with said source and secondary windings, terminals of like polarity on said secondary windings being connected together, said control device connected between said source and one of the primary windings, and means for shunting said control device, said device normally being energized by a voltage resulting from phase shift in the magnetic field of the last said primary winding due to the reactive characteristics of said control device, which voltage is reduced to substantially zero with said device shunted by the said means.

3. In combination, a source of alternating current, a pair of transformers each having primary and secondary windings, and an impedance device; connections from one of said primary windings directly to said source; a series circuit including the other of said primary windings, said source and said impedance device; and connections between terminals of like polarity on said secondary windings, said impedance device being energized by a voltage thereacross proportional to the out of phase relation of the voltages of said secondary windings due to the reactance of said device.

4. In combination, a source of alternating current, a pair of transformers each having primary and secondary windings, an impedance device, and a low resistance shunt circuit connected across said impedance device; connections from one of said primary windings directly to said source; a series circuit including the other of said primary windings, said source and said impedance device; and connection between terminals of like polarity on said secondary windings; said impedance device adapted to be energized by a voltage thereacross proportional to the out of phase relation of the voltages of said secondary windings due to the reactance of said device, which voltage is reduced substantially to zero by the connection of said shunt circuit across said device whereby the reactance of said device is substantially ineffective in said series circuit.

5. The combination set forth in claim 4 wherein said low resistance shunt circuit comprises a train occupied track section in a railway block signal system, exit of the train from said track section operating to open the shunt circuit across said device.

6. The combination set forth in claim 4 wherein said low resistance shunt circuit comprises a train occupied track section in a railway block signal system, exit of the train from said track section operating to open the shunt circuit across said device; and wherein said impedance device constitutes the operating winding of a relay system adapted to actuate signal and control apparatus in said block system, said device being energized with said track section unoccupied.

7. The combination set forth in claim 4 including signal means in one of the connections between said secondary windings responsive to the circulating current in said secondary windings; and wherein said low resistance shunt circuit comprises a train occupied track section in a railway block signal system, exit of the train from said track section operating to open the shunt circuit across said device for altering the phase relation of the voltages in said secondary windings and the circulating current therein, whereby said signal means indicates the condition of said track section.

8. In combination, an impedance device, and means forenergizing said device; said means comprising a source of alternating current, phase controlled voltage regulating means connected with said source and operative to provide balanced potentials at the output thereof, and means for connecting said impedance device across said balanced potential output for introducing a phase displacement in said phase controlled voltage regulating means for producing a difference of potential proportional to the phase displacement for energizing said device.

9. The combination set forth in claim 8 and including means for shunting said device for effectively removing said phase displacement and reducing said potential difference substantially to zero, whereby current in said shunting means is substantially zero.

10. The combination set forth in claim 8 and including means for shunting said device for eflectively removing said phase displacement and reducing said potential difference to zero, the last said means comprising the rails of a track section in a railway block signal system and electrically bonded means carried by a train on said rails in bridging relation thereto, said device is deenergized under control of a train in said track section.

JOHN C. MCDONALD.

whereby 2O 

